Neonatal characteristics
Table 4 presents the neonatal characteristics of singletons and twins in the different post-thawed culture period groups. No significant differences were present in regard to gestational age, preterm labor rate, birthweight, low birthweight rate, cesarean section rate, sex ratio and congenital malformation rate between the two groups. The results also indicated that the singleton had a higher average gestational age and birthweight as well as a lower cesarean section rate, preterm labor rate and low birthweight rate than the twins in the groups S and L (P values were all less than 0.001).